A large demand exists in contemporary society for underground piping, which is used to convey fluids from one location to another. The pipeline is buried to protect it, and it is also usually coated with a plastic or other protective material to extend the life of the pipeline by preventing corrosion.
To lay an underground pipeline, a back hoe, trencher or the like is used to create an excavated trench, and the excavated soil and rock, which is commonly called spoil, is piled to one side of the excavation. The pipeline is then laid in the excavation. After the pipeline is laid in the excavation, it must be covered with earth material. However, it is important that rocks in the spoil do not come into contact with the pipeline, which could breach the protective coating and cause unnecessary corrosion of the pipeline. For this reason, it is common to fill in a portion of the excavation surrounding the pipeline with fine material, which is commonly called padding material. In the past, sand or other fine material usually had to be purchased from remote locations and hauled great distances to the pipeline location for this purpose. However, sand padding is labor intensive, and it also requires many trucks and loaders, which can cause problems along the narrow right-of-way of the pipeline project.
More recently, pipeline padding machines have been developed that move along the pile of excavated spoil and continuously collect spoil material, separate from the spoil fine material suitable for pipe padding, and convey the padding material into the excavation to pad the pipeline. These earlier padding machines were an improvement over sand hauling sand padding, however, the costs associated with pipeline construction and pipeline padding are considerable, and every increase in efficiency can translate to large savings in time and labor.
For example, the pipeline environment can present excavated spoil that is wet, sticky, and rocky, such spoil being difficult to load onto the machines for processing into padding material. Such spoil conditions can slow down the padding process. Thus, there is a need for improved padding apparatus that has better material handling ability and is more efficient at collecting and loading spoil material for processing into padding material.